How to Geek:

• The Option key on a Mac is a modifier key that is used to change the functions of menus and keyboard shortcuts.
  Use Option key to do things like force quit unresponsive apps, fine-tune the volume and brightness, bypass confirmation when shutting down or deleting files, and more.
  Try the Option key throughout the macOS desktop and in different apps to find useful new shortcuts and functions.

Do you know what the Option key on your Mac keyboard does? It’s actually one of the best little-known features in macOS, and hides countless extra settings and shortcuts. Let’s take a closer look.